皮肤镜在寻常型银屑病与慢性湿疹鉴别诊断中的意义

Roles of dermoscopy in differential diagnosis of psoriasis and eczema

目的描述斑块型银屑病和慢性湿疹的皮肤镜特征，探讨皮肤镜在银屑病诊断以及鉴别诊断中的应用价值。方法回顾性分析2013年112月至2014年5月在北京协和医院皮肤科门诊就诊行皮肤镜及皮肤组织病理检查的斑块型银屑病和慢性湿疹患者，共68例。评估皮肤镜下血管形态、血管分布、鳞屑颜色、鳞屑分布4方面的皮肤镜特征。以病理结果为疾病诊断的金标准，计算皮肤镜各特征出现的频率以及诊断的敏感度、特异度、阳性预测值、阴性预测值。结果共选取31例斑块型银屑病患者和37例慢性湿疹患者的皮肤镜照片，亮红色背景（敏感度为71．0％，特异度为75．7％）上规则分布（敏感度为80．6％，特异度为73．0％）的点状血管伴有白色鳞屑（敏感度为71．0％，特异度为83．8％）高度提示斑块型银屑病，暗红色背景上片状分布点状血管伴有黄色鳞屑提示慢性湿疹。此外，环状血管和发夹样血管对于诊断斑块型银屑病有很高的特异度（分别为91．9％和94．6％）。结论银屑病和慢性湿疹具有特征性的皮肤镜下表现，皮肤镜在银屑病的诊断和鉴别诊断中具有很大的价值。

Objective To describe the dermoscopic patterns of plaque psoriasis and chronic eczema and explore the roles of dermoscopy in their diagnosis and differential diagnosis. Methods A total of 68 patients with plaque psoriasis or chronic eczema were recruited from our department from December 2013 to May 2014 to undergo dermoscopic and histopathological examinations. Dermoseopic features of vascular morphology, vascular arrangement, background color, scale color and scale distribution were evaluated. Sensitivity, specificity, positive predictive value and negative predictive value were calculated for predefined dermoseopic criteria in relation to the diagnosis of plaque psoriasis. Results Thirty-one patients with plaque psoriasis and 37 patients with chronic eczema were included. Dotted vessels in a regular arrangement （ sensitivity 80. 6%, specificity 73.0% ） over a light red background （ sensitivity 71.0%, specificity 75.7% ） and white scales （ sensitivity 71.0% , specificity 83.8% ） were highly predictive for the diagnosis of plaque psoriasis. And chronic eczema more commonly showed yellow scales and dotted vessels in a patchy arrangement over a dull red background. Characteristic vascular structures of hairpin vessels and red loops were also found to be highly specific （ 91.9% , 94. 6% ） for the diagnosis of psoriasis. Conclusions Plaque psoriasis shows specific dermoscopic patterns compared with chronic eczema. And dermoscopy is valuable in the diamaosis and differential diagnosis of psoriasis.